The present invention relates to an electronic circuit board and a method for making an electronic circuit board and more particularly, to a multi-layer electronic circuit board having metallized apertures which are selectively isolated and/or disconnected from an electrical ground plane and further having selectively formed air bridges and/or crossover circuits.
Multi-layer circuit boards operatively receive electronic components and allow the received components to be desirably interconnected and to selectively and cooperatively form electrical circuits. Particularly, these components are operatively received upon opposed board surfaces and within certain interior portions of the board, thereby desirably allowing each of the electronic circuit boards to contain a relatively large amount of components which efficiently, respectively, and densely populate the respective boards.
It is desirable to allow each of the component containing surfaces or portions of a created and/or formed electronic circuit board to communicate and/or be selectively interconnected, thereby allowing the contained electronic components to cooperatively and selectively form a relatively large number of desired electrical circuits. This desired communication and/or interconnection typically requires the use of shared electrical ground planes, the transmittal of electrical power and/or control type signals between some or all of the component containing surfaces or board portions, and/or the connection of components on each of the opposed surfaces and/or within and between certain of the interior portions and the top and/or bottom and/or other board surfaces.
This desired interconnection typically requires that one or more holes be formed or drilled through each of the circuit boards, thereby creating at least one xe2x80x9cthrough holexe2x80x9d or xe2x80x9cviaxe2x80x9d traversing between each of the opposed component containing surfaces and through the various interior circuit board portions. Typically this drilling process is relatively complex and time consuming, thereby increasing the overall circuit board production cost. This drilling process also undesirably damages and/or destroys many of the circuit boards, thereby further increasing overall production costs.
Further, it is desirable to form xe2x80x9cair-bridgesxe2x80x9d or xe2x80x9ccrossover type circuitsxe2x80x9d upon one or more selected surfaces and/or within certain component containing portions of the formed circuit board in order to allow multiple levels of circuits and/or electrical interconnections to be formed upon a single board surface and/or within a certain component containing portion of the circuit board, thereby desirably increasing the amount of electrical circuits which may be created upon and/or within the created circuit board (e.g., increasing the density of the contained electrical circuitry).
These xe2x80x9cair-bridgesxe2x80x9d or crossover circuits are typically formed by rather complicated, costly, and time consuming processes. The formed bridges and crossover circuits further do not typically and efficiently accommodate certain desirable circuit board interconnection processes, techniques, and/or methodologies such as and without limitation, the use of relatively heavy wire bonding (e.g., aluminum wire having a diameter of about five to about twenty millimeters) or the direct connection of components to a surface of the board.
There is therefore a need to provide an electronic circuit board and a method for producing a multi-layer electronic circuit board which overcomes some or all of the previously delineated drawbacks of prior electronic circuit boards and methods for making a circuit board, which selectively allows grounded and non-grounded xe2x80x9cviasxe2x80x9d to be desirably and selectively and efficiently formed in a cost effective manner, and which further allows for the efficient and selective formation of air-bridge members or crossover circuits which desirably accommodate diverse types of circuit interconnection processes, and which increase the circuitry density within the formed electronic circuit board.
It is a first object of the present invention to provide an electronic circuit board and a method for producing an electronic circuit board which overcomes some or all of the previously delineated drawbacks of prior multi-layer electronic circuit boards and of prior electronic circuit board forming methodologies and techniques.
It is a second object of the invention to provide a method for producing a multi-layer electronic circuit board which overcomes some or all of the previously delineated drawbacks of prior multi-layer electronic circuit board forming methodologies and techniques, which allows for the formation or creation of an electronic circuit board which selectively receives various electronic components, which allows for the selective, efficient, and reliable formation of metallized apertures, within the formed and/or created electronic circuit board, which cooperatively allow for communication by and between these various electronic components and which further cooperatively allow for the selective interconnection of these contained components.
It is a third object of the invention to provide a method for producing a multi-layer electronic circuit board which overcomes some or all of the previously delineated drawbacks of prior multi-layer electronic circuit board forming methodologies and techniques and which allows for the selective formation of metallized apertures within a circuit board, which may be selectively connected or disconnected and/or selectively isolated from a formed electrical ground plane or bus.
It is a fourth object of the invention to provide a method for producing a multi-layer electronic circuit board which overcomes some or all of the previously delineated drawbacks of prior multi-layer electronic circuit board forming methodologies and techniques and which allows for the selective and efficient formation of air bridges and/or crossover circuits and/or crossover members which are adapted to accommodate a wide variety of component interconnections, assemblies, techniques, and/or methodologies.
According to a first aspect of the present invention, a method for making an electric circuit board is provided. The method includes the steps of providing a first member having a core which is contained between a first and a second layer of material; providing a second member having a core which is contained between a first and a second layer of material; providing a first and a second layer of a first material; providing a third member; removing a portion of the top and the bottom layer of the first member, thereby exposing a first and a second portion of the core of the first member; removing a portion of the top and bottom layer of the second member, thereby exposing a first and a second portion of the core of the second member; creating a first pre-circuit assembly by attaching the first layer of first material to a first surface of the third member, attaching the second layer of first material to a second surface of the third member, attaching the first member to the first layer of first material, and attaching the second member to the second layer of first material; creating an aperture through the first pre-circuit assembly, thereby exposing a first surface of the first pre-circuit assembly within the aperture; applying an electrically conductive material to the exposed first surface of the third pre-circuit assembly; and selectively removing portions of the core, thereby creating at least one air-bridge and forming an electrical circuit assembly.
According to a second aspect of the present invention a circuit assembly is provided. The circuit assembly is made by the process of forming a first pre-circuit assembly having a first core member having a first and a second surface, a first plurality of electrically conductive members disposed upon the first surface, and a second plurality of electrically conductive members disposed upon the second surface; forming a second pre-circuit assembly having first and second circuit boards which are selectively attached to a dielectric adhesive material and which cooperatively form a separation region; coupling the dielectric adhesive material to the second plurality of electrically conductive portions; removing certain portions of the first core member, thereby forming a pedestal portion which abuts the separation region; extending the separation through the pedestal portion, thereby forming a circuit board.
According to a third aspect of the present invention, a circuit board is provided and comprises a first electrically conductive member having a first and a second surface; a first dielectric member which is coupled to the first surface; a second dielectric member which is coupled to the second surface; a first circuit assembly having a second electrically conductive member which is coupled to the first dielectric member, the first circuit assembly further including a third electrically conductive member and a first core member which is contained between the second and the third electrically conductive members and which includes at least one air-bridge; and a second circuit assembly having a fourth electrically conductive member which is coupled to the second dielectric member, the second circuit assembly further including a fifth electrically conductive member and a second core member which is contained between the fourth and the fifth electrically conductive members and which includes at least one air-bridge, the second circuit assembly cooperating with the first circuit assembly and with the first and second dielectric material and with the first electrically conductive member to form a multi-layer circuit board.